This white paper and accompanying solution show implementations that improve end-to-end message order delivery between a pair of receive and send ports while running concurrent orchestrations. The architecture discussed implements a common resequencer pattern to solve this problem.

The solution introduces the notion of a ticket for every message traveling through the processing chain. Business orchestrations can take the necessary time to process the messages in any order. As long as the ticket is propagated in each message, the messages can be resequenced on the way out.
It is important to define the boundaries of ordered delivery. For this solution, order begins at the BizTalk Server receive port, and the goal is to maintain this order until the messages are sent out of BizTalk Server.